Primary hepatocellular carcinoma is a common cancer. Many patients are found with intermediate-advanced stage, rapid development, poor treatment and high mortality. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) can discover the early lesions and therefore plays an important role in diagnosis, treatment and prognosis of patients with hepatocellular carcinoma. It especially has obvious advantages in detecting metastasis and monitoring recurrence. However, 18F-FDG PET/CT imaging has poor quality and low diagnosis rate. Understanding the advantages and limitations of 18F-FDG PET/CT can provide better basis for clinical diagnosis and treatment for hepatocellular carcinoma patients. This article briefly introduces the research and application of 18F-FDG PET/CT in the diagnosis and treatment of hepatocellular carcinoma.